Specifically, Ross pointed the finger at China, whom he called "the most protectionist country of very large countries."

Ross's comments come after China's President Xi Jinping sought to cast himself as a fierce defender of free trade. "Whether you like it or not, the global economy is the big ocean you cannot escape from," Xi said in a speech on Tuesday at the World Economic Forum in Davos. "No one is a winner in a trade war."

In fact, Ross's comments seemed directly aimed at China when he said: "It's one thing to talk about free trade. We would like to have our trading partners also practice free trade."

Ross, who made a fortune as a turnaround artist that resurrected dying manufacturing businesses, said the U.S. should provide access to its vast market to "nations who agree to play by our standards of fair trade."

But countries that don't "play by the rules" should "get punished -- and severely," he said.

Trump has suggested tariffs as one way to retaliate and Ross seems to support that option. He said tariffs "play a role both as a negotiating tool and, if necessary, to punish offenders who don't play by the rules."

Asked if he'd oppose a 35% tariff, Ross said, "It's a complicated issue whether you should have one flat tariff on everything or whether it should be more tailored."

Many have warned that Trump tariffs risk a trade war. That's what happened during the Great Depression after the U.S. raised tariffs on thousands of goods with the Smoot-Hawley Act. Other nations retaliated and the global economy suffered.

Ross has sharpened his rhetoric in recent months, after previously urging politicians to temper their anti-China comments. CNN's KFile reported this week about a 2007 speech from Ross, in which he expressed worry about the rise of a "protectionist monster" in the West and "mindless China bashing."

The backlash against anti-globalization has helped kill the Trans-Pacific Partnership trade agreement. Ross explained why he has come out against the controversial trade deal after originally supporting it.

Ross said he discovered inconsistencies in TPP, including a section that allows for more than 60% of the components that go into making cars to come from outside TPP countries and still enjoy member benefits.

But Ross plans to hold on to nine investment vehicles that contain shipping, mortgage lending and real estate financing assets. Ross explained he will keep these assets "solely as a passive investor."

During the hearing, Democratic Sen. Richard Blumenthal noted that this process was "enormously complex, challenging and costly" to Ross personally and suggested Trump should follow his lead. Trump has been criticized for declining to sell his stake in his business empire.